TITLE: GCN CIRCULAR NUMBER: 8367 SUBJECT: GRB 081008 optical upper limit DATE: 08/10/13 12:04:46 GMT FROM: AAVSO GRB Network at AAVSO Peter Nelson (Ellinbank, Victoria, Australia) reports to the AAVSO International High Energy Network the following optical observation of GRB081008 (GCN #8344 Racusin et al.; GCN #8343 Rykoff et al.): Peter Nelson has obtained a limiting magnitude on the optical afterglow of GRB081008 (Racusin et al., GCN #8344). The optical afterglow position RA: 18:39:50, Dec: -57:25:52 found by Rykoff et al. (GCN #8343) was observed for a total of 480 seconds using a 0.32-meter Newtonian with an SBIG ST8XE CCD and an R filter. The mid-point of the observations was 2008 Oct 09.4150 UT, approximately 14 hours after the burst. The afterglow was not detected to an upper limit of R=18.2, using USNO-A2.0 star 0300-34687382 (R=11.8) as the comparison. This upper limit is consistent with the R-band magnitude of R=18.46 on 2008 Oct 08.9951 observed by Cobb et al. (GCN #8356). A detailed report of these observations is available on the AAVSO website at ftp://ftp.aavso.org/grb/PeterNelson_081008_2454752.03073_.txt A fits image is available at ftp://ftp.aavso.org/grb/PeterNelson_081008_2454752.03073_.fits The AAVSO thanks the Curry Foundation for their continued support of the AAVSO International High Energy Network.